The science magazine of Imperial College

Bang Goes The Theory – Sugar

Bang Goes The Theory (BBC 2) set out to find the truth about all things sugar, and in its quest stumbled across many surprises. In fact, the episode could be seen as a chain of myth-debunking surprises: eleven perhaps.

Surprise 1. (Ignorantly) I assumed that most sugar in the UK came from cane grown in some sun-drenched foreign land. Not so. Most of our sugar comes from East Anglia and grows as sugar beat which looks like a fat turnip. In Britain, seven thousand sugar beat farmers produce nine million tonnes of sugar every year.

Surprise 2. It’s always surprising when what you thought was a complex industrial process turns out to be simple. Every episode of Bang has lovely, lively, blue-eyed Jem demonstrating a common scientific process using a rudimentary set up. This week he made a mini sugar refinery. Jem (in constant wonder at the words leaving his mouth) chopped up the beat and boiled it to draw out the sucrose. He was left with sweet, muddy water. But when he added milk of lime and carbon dioxide they combined to make chalk. And – enter surprise number two – all the non-sugary debris sank to the bottom. This reminded me of isinglass, a substance taken from the swim bladders of dried cod. It is used in the clarification of beer and wine and causes problems of conscience for pint-guzzling vegetarians.

It also reminded me of Luis Federico Leloir, an Argentinean biochemist who won the Nobel Prize for Chemistry. Like Jem, Leloir had to make a home-made centrifuge. Without financial or political support during the Argentinean dictatorship, Leloir constructed the improvised instrument using a car tyre inner tube filled with salt and ice. It’s remarkable how scientists, like Leloir, adapt to overcome, and even excel in, conditions that are so hostile to science.

Anyway, surprise 3. I was a bit shocked that the following line escaped the script-reader’s thinking: “I’ve decided it’s best to come inside for the high pressure finale!”

Surprise 4. A sugar-coated myth debunked: white sugar is no more processed than brown sugar. As Jem’s centrifuge whirrs, a syrupy molasses drains from the sugar crystals which remain pure white. To make brown sugar the molasses is re-added to the crystals. So white sugar is not more bleached than brown – or made up of ground bone as a hippy once told me.

Surprise 5. Sugar stimulates the release of the endorphin dopamine.

Surprise 6. A different presenter, Liz, tasted – note, just tasted – a glucose drink and a drink without glucose. She underwent an experiment to test her reactions. Just the taste of glucose massively sped up her reactions. Apparently sugar enhances our ability to ignore irrelevant information.

(Mini) surprise 7. Excess sugar gave a doctor a fatty liver. A word of warning in an otherwise pro-sugar show.

Surprise 8. This will get your eyebrows reaching for your hairline. Which do you think contains the most sugar: tomato soup, a diet tomatoey pasta dish or a cheeseburger with chips? Answer: the diet pasta dish. To replace low fats and salt, sugar is used to give diet food more flavour.

Surprise 9. Artificial sweeteners, including aspartame, do no harm.

Surprise 10. Half of all vaccines are discarded because they spoil out of a fridge. So – surprise 11 – sugar can be mixed with the vaccine and dried onto a fibre membrane. It can then be stored at room temperature without deteriorating. When saline solution is flushed through, the sugar dissolves releasing the vaccine. So people in remote areas can be more easily vaccinated.